From the Guidelines
Medical decision-making capacity is determined by evaluating a patient's ability to understand, retain, and weigh relevant information, as well as communicate a clear decision, as outlined in the most recent guidelines 1. To determine medical decision-making capacity, clinicians should assess four key abilities in a patient:
- Understand relevant information about their condition and treatment options
- Retain that information long enough to make a decision
- Weigh the risks and benefits of different options and explain their thought process
- Communicate a clear, consistent choice This assessment is decision-specific, meaning a patient may have capacity for some decisions but not others, depending on complexity, as noted in a 2020 policy statement by the American Thoracic Society and American Geriatrics Society 1. Capacity can fluctuate based on factors like medication effects, time of day, or disease progression, so repeated evaluations may be necessary, and clinicians should consider delaying important treatment decisions until reversible causes of impaired capacity are addressed, as suggested by a 2020 study 1. Important considerations include avoiding confusion with psychiatric diagnoses, recognizing that capacity differs from legal competency, and consulting with psychiatry or ethics committees when capacity is questionable, as recommended in a 2020 policy statement 1. No specific standardized test is universally required, though tools like the MacArthur Competence Assessment Tool can supplement clinical judgment, and institutions should implement strategies to determine whether seemingly unrepresented patients are, in fact, unrepresented, including carefully assessing medical decision-making capacity and diligently searching for suitable surrogates, as outlined in a 2020 policy statement 1.
From the Research
Determining Medical Decision-Making Capacity
To determine medical decision-making capacity in a patient, several factors must be considered. The patient's ability to understand the benefits and risks of a proposed treatment, appreciate the consequences of their decision, and reason through their thought process are all crucial components of medical decision-making capacity 2.
Assessment of Capacity
Capacity is typically assessed intuitively at every medical encounter, but a more formal evaluation may be necessary if there are concerns about a patient's decision-making abilities 2. Several formal assessment tools are available to help with capacity evaluation, including the Aid to Capacity Evaluation (ACE), the Hopkins Competency Assessment Test, and the Understanding Treatment Disclosure 3.
Evaluation Instruments
A review of published instruments for assessing healthcare decision-making capacity found 17 different assessment instruments, each with its own format, structure, and targeted population 4. While there is no gold standard for healthcare decision-making capacity assessment, instruments like the ACE have been shown to be useful in evaluating capacity 3.
Clinical Judgment and Ethical Considerations
Decision-making capacity evaluation is not only a descriptive task but also an inherently normative one, involving ethical reasoning and dependent on the values held by clinicians 5. A clinician's guide to decision-making capacity emphasizes the importance of disclosing adequate information to patients and determining their understanding and appreciation of that information 6.
Key Factors in Determining Capacity
Key factors in determining medical decision-making capacity include:
- The patient's ability to understand the situation and make a choice in light of that understanding 2, 6
- The patient's appreciation of the consequences of their decision 2
- The patient's ability to reason through their thought process 2
- The patient's ability to communicate their wishes 2
- The use of formal assessment tools, such as the ACE, to evaluate capacity 3